Pneumatically-fed crushing and sifting device



July 1927' E. BARTHELMESS FNEUMATIC ALLY FED CRUSHING' AND SIFTING DEVICE Filed Aug. 15, 1925 /n yen/or.-

Patented July 12, 1927,

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UNITED STA -'EMIL BART'HELME SS, OF DUSSELDORF-OBERKASSEL GERMANY.

' 'rivEuMArIcALLY-mncm'isnme AND srrrmo :oEvIoE.

Application filed August 15, 1925, Serial No. 50,481, and in Germany August 22, 1924.

This invention relates to a crushing and separating device of the kind in which the materials are fed by suction through a separator where the coarse materials are divided off by gravity and returned through a crusher to the feeding duct.

This return of the materials to the feeding duct entails difficulties. owing to' the return pipe being vunder the influence of the suction in the separator.

The object of the present invention is to obviate these difficulties, and the invention consists in neutralizing the suction effect in the return pipe by arranging the latter so that it opens into the. feeding duct in the direction in which the air and the mate rials travel. An injector effect will thus -be obtained whereby the materials are attracted from the crusher tothe feeding duct and whereby the suction produced at the separator endof the pipe is neutralized. Preferably, a gravity-operated flap is arranged at the junction between the feeding duct and the return pipe, in advance of the latter, so that, while it can yield to let the materials pass through, it tends to close the feeding duct! This arrangement intensifies the injector effect and induces the coarse material to separate easily from the finer materials and return to the crusher.

Fig 1 of the accompanying drawings represents a diagrammatic view of. the arrangement, and

Fig. 2 is a diagrammatic view showing tlhe arrangement of the flap in the feeding uct.

A pneumatic separator (2 contains an up-.

separator and extract to the exhauster i which delivers them into a silo is having a sacking nozzle 1. The

coarser materials fall by gravity to'thebottom of the separator wherethey enter the 1' pipe p which returns them, through .a crusher 0, to the feeding duct 0 at g. The pipe 9 opens obliquely into the duct 0 in the direction in which the air and the materials travel in the latter. It will thus be subjected to an injector effect which neutralizes the suction at the separator end of the pipe and which tends' to maintain the coarse materials in circulation until they are fine enough-"to be delivered to the silo 70.

Preferably a gravity-operated valver is arranged in the duct 0 in advance of the:

pipe p, as shown in Fig. 2, so as to tend to close the duct. This flap, which opens under the influence of the suction and which also yields to the materials, intensifies the injector effect in the pipe p. a

A pipe n may be led from the silo k to the duct 0 so that the air from the exhauster i can, after it-has been freed inthe silo from suspended particles, be returned to the duct for further use. The silo has an air vent m through which surplus air, admitted by leakage, can be discharged. L A shifting device of this kind lends itself to the erection of large'sifting and crushing plants. It has the advantage that the sifting and feeding of the materials are brought about without mechanical elements other) than the exhauster.

I claim: t

1. A separating and crushing device com prising a pneumatic separator, a feeding not having a horizontal portion and a vertical portion which latter rises into said separator, a feeding hopper opening into the horizontal portion of said feeding duct, an exhauster communicating with the upper part of the separator so as to draw the materials through the feeding duct into the the finer particles from the latter, a crusher, and a return pipe for leading the coarser partlcles from the lower part of the separator to the crusher and thence of the feeding duct, the return pipe beingarranged so as to open obliquely into the feeding duct'in the direction; in which the materials travel, substantially as and for the I purpose set forth.

2. In a sifting and crushing device according, to claim 1, a gravity-operated flap arranged in the feeding duct at the junction betvveem said duct and the return pipe .in advance of the latter so that it tends to close the duct and so that it can yield to the suction and to the materials, substantially as purpose set forth.

and for the v EMIL BARTHELMESS, 

